* {
  box-sizing: border-box;
}
body {
  height: 100vh;
  overflow: hidden;
  margin: 0;
  /* 直接flex布局 */
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  /* 背景图片的定位 */
  background-position: center center;
  background-size: cover;
  transition: 0.4s;
}

/* 给body添加伪元素，创造透明度的图层 */
body::before {
  content: '';
  position: absolute;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.7);
  z-index: -1;
}
.container {
  width: 60vw;
  height: 60vh;
  /* 最小化影响 */
  position: relative;
  /* 超出隐藏 */
  overflow: hidden;
  /* display: flex;
  justify-content: center;
  align-items: center; */
}

.arrow {
  position: fixed;
  top: 50%;
  transform: translateY(-50%);
  border: 0;
  background-color: transparent;
  color: #fff;
  cursor: pointer;
  font-size: 30px;
  font-weight: bold;
  padding: 20px;
}

.left {
  left: calc(15vw - 65px)
}

.right {
  right: calc(15vw - 65px)
}

.slide_img {
  /* 设置全屏宽高 */
  width: 100vw;
  height: 100vh;
  opacity: 0;
  background-position: center center;
  background-size: cover;
  transition: all 0.3s linear;
  /*  */
  position: absolute;
  top: -15vh;
  left: -15vw;
  z-index: 1;
}

.slide_img.active {
  opacity: 1;
}